Did I understood correctly that we now have tools that will likely provide more clues to the disappearance but the text mentions no particular clue, yet? (I read it diagonally trying to dodge the ads)
That was my read. They can now identify species of very fragmentary bone remains via collagen protein matching. They didn't say what if anything clues this would/could lead to.
When I go fossiling in Florida almost every large find is from the Pleistocene or Holocene, when Florida was not covered by the ocean. Identifying the bone fragments is always a big puzzle that involves a good bit of study and reference books. A fun puzzle for sure, but sometimes you end up with a find that you just can't place. It would be great to have a technique such as ZooMS to positively identify the unidentifiable.
I still believe it was due to Humans. Megafauna disappeared around the time Humans reached the Americas, way too much of a coincidence to me. These mammals were there before the Ice Age and I think the coming of the ice age was just as hard on then as the retreating ice.
It's the same story in Australia. Several large slow creatures that disappeared shortly after the arrival of humans. I think trying to pin the blame solely on the weather is simply because it's much more in sync with the "stewards and custodians of the land" narrative that is currently so fashionable.
The extinction doesn't seem to have happened 50k years ago in North America. That seems to have been made up by whoever wrote the headline. The date of 50k years ago does not seem to appear anywhere in the linked academic paper, does not correspond to climate change at the start of the current interglacial, and does not correspond to evidence of the arrival of humans in North America. Even the body of the phys.org article doesn't say the extinction happened then.
There were wooly mammoths alive in 2000 BC, 600 years after the Great Pyramid was built. There is evidence of humans and mammoths being in north America together.
My thoughts as well. If the native Americans had the technological ability to extinct the Buffalo they would have done it. Just as they killed off many more fragile species and other tribes. Life in pre Colombian America was just as nasty as it was in post Colombian America.
> If the native Americans had the technological ability to extinct the Buffalo
I think it's more the case of if they didn't have the ability to create a balance. Things like the creation of the Amazon rainforest and the domestication of corn, potatoes, tomatoes, quinoa, llamas, etc. were because Native Americans figured out how to do those things. It's likely though that the first Native Americans just didn't know that stuff yet and accidentally ate all the mammoths or whatever because they didn't yet have a tradition of "only eat the mammoths when the third moon rises after Orion returns" or whatever. Those kinds of cultural traditions are social technologies, and they enable ways of life that would otherwise collapse in a few decades.
In the Pacific, Hawaiians and others had seemingly useless taboos like "women can't eat bananas" but following the taboo rules sustained a huge population (estimates for Hawaii vary, but it was at least a significant fraction of the current population without international shipping!).
In the Amazon, manioc is a great staple crop… as long as you serve it exactly right so you don't slowly poison yourself. They figured that out, but I'm sure there were many generations that got it wrong before they got it right.
So I don't think the framing should be "plains Indians didn't know how to kill off the buffalo." Rather a) plains Indians didn't have horses pre-European contact, so that whole way of life didn't exist until modernity and b) balancing with nature is a learned cultural achievement.
> Things like the creation of the Amazon rainforest
Kind of a ridiculous myth when you consider the diversity of life uniquely adapted to the various micro environments of the amazon rainforest. It would be multi-million-year terraforming project.
No, it's not about any woo woo natural balance. Mammoths were really easy to kill and if they were anything like their elephant cousins would have taken 10-15 years to reach sexual maturity. Their population would also be considerably lower and larger animals are more sensitive to change because they reproduce slower and their are fewer of them.
Buffalo on the other hand reach sexual maturity at 2-3 years, there were many more of them. They replaced their populations faster.
The first humans in North America didn't extinct buffalo because they couldn't, they would have had to have much more population and civilization progress before that became a risk.
You are right. But you are trying to educate a political vital mythos away, that just can not die. The noble savage always wins, as it is a coreconcept of the back to nature "movement".
It's not "noble savage" to note that Native Americans domesticated numerous crops used globally today and that such domestication was a technological achievement, much like the domestication of the horse in central Eurasia or the cultivation of rice in Asia. It's basically the opposite idea: rather than being "naturally" in balance with nature, Native Americans figured it out the same way humans figured everything else, through trial and error, and at the cost of countless lives. It is closer to the stereotype to believe that Plains Indians had some kind of timeless way of life, instead of recognizing they occupied a temporary historical niche that lasted between the introduction of the horse and the near extinction of the buffalo. Introducing history to our understanding of Native American achievements and failures is the only way to treat them as equally human as every other culture.
I thought it was accepted that Australian megafauna went extinct due to humans. But could also be a combination of factors e.g weakened by a climatic shift then finished off by newly arrived human predators
What about the inverse? Humans expanded to the Americas after megafauna populations were reduced. Its easy to look at things like poaching and assume humans have always been the dominate species. But megafanua like moose or brown bears are still dangerous, even today.
We don’t spend much time dealing with mega fauna like moose or brown bears anymore so are generally unprepared for it. But if it was a bigger part of our lives I’m pretty sure we would dominate even with cavemen level tools.
I think a lot of the megafuauna have bones found near humans and other signs of hunting and the inverse meaning human bones with animal bites isn’t as common.
Yeah, I am playing a bit of devils advocate here. Things like glyptodon would have been easy targets in theory.
I do wonder if human processing of animals makes their bones more likely to find. Most of what we find about ancient humans comes from trash pits. Animals don’t always bring food to the same place, and scavengers can further distribute and decompose parts.
There have been cases of human bone caches made by animals, like in the Sauida Arabian lava tube. But that seems like a relatively ideal condition for long term preservation.
Another fact that supports this perspective is that the North American megafauna survived through numerous cycles of ice ages prior to the arrival of humans. There was nothing particularly unique or special about the last ice age, the only real difference was the presence of humans.
One thing I find particular interesting though, is that there are likely two unique extinction events. One around 50KYA, that coincides with what I personally believe was the first peopling of the Americas, and another around 16KYA, which coincides with the arrival of North Americas current indigenous population.
Yep. I can't prove it but I know it's true. Us humans have caused too much environmental harm to list, but here are the top hits:
- Chopped down all the trees on Easter Island
- Overharvested laserpicium in Cyrenaica (Libya)
- Hunted passenger pigeons to extinction
- Hunted bison nearly to extinction
- Overfished sardines off Monterey Bay California
Tragedy of the Commons is the default setting for most all of human history, while sustainability like ancient Japan and modern regulations in most countries are the exceptions. And, anthropogenic climate change is indirectly leading to untold mass extinctions on a global scale.
My problem with humans did it, even though it seems most likely, is there weren't very many humans, and the Americas are so large. Wouldn't some isolated populations continue to exist? Also, where are all the megafauna remains in middens?
My problem with the notion that humans caused the extinction of large mammals is that humans supposedly originated in Africa and large mammals weren't extinct there. So how did that happen?
The large animals evolved along side humans and learned to fear/kill us on sight. All the other mega fauna had to deal with fully modern humans who already knew how to hunt.
I just don't buy that. It's too hand wavey. Natural instinct is to fear the unknown, and to respond quickly to threats. Saber tooth cats roamed the continent too and there is plenty of evidence they hunted humans, along with bears that continue to hunt humans to this day. But there were also dire wolves, giant bison, cave bears, and many other large species that went extinct but for which we have smaller forms of alive today. Something must have occurred environmentally that led to the rapid deaths of large species.
It's also not as if we have evidence of large populations of humans in the glacial era. You would need a modern civilization with at least metallic tools to spread far enough and wide enough to kill off multiple major species.
Right, well during the age of sail we had already achieved gunpowder, steel and iron working, and landing on small islands with navigation era tech it is quite easy to dominate or change a small ecosystem by cutting down trees, hunting excessively, introducing livestock and other invasive species, etc.
In the ice age the tools were bone and stone. And the lack of agriculture meant that human populations were kept small by available resources by default. The lack of transportation or even domestication of animals in the Americas at the time meant that all travel was on foot. To dominate species like the mastadon, giant ground sloth, cave bear, dire wolf, etc on two continents was just something humans weren't capable of at the time.
Hunting was still risky and labor intensive. Arrows didn't have metal heads. Range was limited. Traveling was risky, both from natural and tribal threats.
It just doesn't add up. The density of humans was probably lower in the Americas than in any other continent (save for Antarctica of course).
> You would need a modern civilization with at least metallic tools to spread far enough and wide enough to kill off multiple major species.
We know humans spread far enough and wide enough in stone age times. Big animals reproduce slowly, and the extinctions happened over centuries or millennia. Metal tools and large populations weren't needed, just stone age hunting techniques and persistence.
I mean dire wolves have just as many pups in a litter as ordinary wolves and go into heat just as often. Same can be said of giant bison, saber tooth cats, etc.
We actually don't know precisely when the extinctions occurred or how long it took for them to occur. All we know is where the gaps in the sparse data set that is the fossil record exist.
It could be that the extinctions actually made it easier for humans to expand and move into those areas after the fact, or that humans uniquely benefitted from the environmental or situational changes that were ongoing.
We know the Younger Dryas was an incredibly intense era of climate change, after the ice age receded it suddenly plunged back into glacial temps for a millenia or two. Very strange and stressful time for species of all types.
In the book The Sixth Extinction, the author posited that you really don't need very sophisticated or systematic hunting to bring megafauna to extinction. Their strategy for survival is to be large, but at the cost of very long reproductive cycles. Slowly but steadily picking one off every now and then can bring them to extinction over the course of centuries, which at the same time means their slow demise and the cause of it can easily go unnoticed.
Megafauna extinction is closely timed with the arrival of humans on just about every continent or island we happened upon. Even Africa is relatively more depauperate compared to the distant past.
Of course not all of them found their end. There are still moose in North America, and giant tortoises in the Galapagos that literally floated away from the coast of South America, where they later went extinct. But there are fewer everywhere.
Larger creatures have long gestation cycles and tend to be very sensitive to any any changes. Even killing a few pregnant females a year could have been enough in a given region.
> Saber tooth cats roamed the continent too and there is plenty of evidence they hunted humans.
We didn't need to hunt dangerous saber tooth cats to get them extincted. We had only to hunt their less dangerous food. They probably couldn't live off the small prey left after the human wave swept the continent.
> Maybe humans didn't originate in Africa. There are many arguments for and against.
Sure, but the arguments against are in the same vein as the argument that, if I draw a circle, it's not a real circle, because I don't have the level of fine control over my hand that would be necessary to produce one of those, and the tip of my pen is too wide.
True, but not really relevant to anything, and in particular unlikely to convince anyone that it's a mistake to call what I drew "a circle".
> and what species are the offspring of a dog-wolf mating considered?
I am not personally aware of standard terminology, but I might say "half wolf" or "wolf hybrid". The wikipedia page is titled "wolfdog". https://en.wikipedia.org/wiki/Wolfdog
There is standard terminology for the offspring of a wolf and a coyote; those are called "red wolves". Wikipedia suggests that they have a taxonomic species name canis rufus, but this is controversial (since they're hybrids).
I do appreciate this and I hope you don't perceive it as "arguing." My biological education is a little sketchy.
Turning it around a little: if some members of a mainland species move to an island and eventually become incapable of interbreeding with the original species, then it is always a new species. True or false?
So "no-interbreeding" is sufficient but not necessary?
> Turning it around a little: if some members of a mainland species move to an island and eventually become incapable of interbreeding with the original species, then it is always a new species. True or false?
I think people would basically agree with this; true enough.
> So "no-interbreeding" is sufficient but not necessary?
Not quite; the example of bacteria, above, disproves the sufficiency of "no-interbreeding".
(Bacteria do mix their genetic material, but they directly exchange it with each other, and then their children are clones of themselves. Imagine if, whenever you had sex, your partner took on some of your traits, and you took on some of theirs. This would obviate the need for your children to draw their traits from more than one parent, and that's how bacteria work.)
There are asexual higher organisms, like some lizards, and they follow the taxonomic example of bacteria in that when two of them are genetically similar enough, we call them the same species despite the fact that - since they can't breed at all - they cannot interbreed.
The fossil example is also incompatible with "no-interbreeding" being a sufficient criterion, though this is a bit less clear than the bacteria example; we can't determine whether two fossils were or weren't able to interbreed. We can be nearly certain that there is some pair of structurally similar-looking fossils out there that we have labeled as belonging to a single species, despite the fact that the individual organisms wouldn't have been able to breed with each other. You could make the argument that this is simply a mistake on our part, and that would have a lot of validity, but even viewed that way it's a mistake that cannot even theoretically be corrected, which causes some conceptual difficulties.
The reason there are so many species concept is that species are just a reflection of the idea that two organisms are "the same". What it means to be "the same" varies in different contexts, according to, without claiming to be exhaustive, (1) what you care about; (2) what is possible in the space you're discussing [pigs can't do the direct genetic exchange that bacteria can]; and (3) what it's possible for you to know.
> I do appreciate this and I hope you don't perceive it as "arguing."
Don't worry about offending me; you seem to be in perfectly good faith so far.
ok. If we know that a species (1) is sexual, and (2) cannot interbreed with an individual of a superficially similar species, then it IS sufficient to say we have two species there. I think I have all the qualifiers :)
Incidentally, today on Facebook someone made the risible claim that since our DNA is 98% the same as a chimp, WE are "98% the same as a chimp."
I pointed out that by that standard, we're also 60% the same as a banana.
You might be interested in the concept of "ring species", which doesn't contradict the principle you just stated, but does conflict with the biological species concept. A ring species is a continuum of interbreeding populations such that the ends of the continuum are not interfertile.
This parallels the phenomenon you see in languages where, for example, any two adjacent villages across a considerable distance will be able to speak to each other, even though villages at opposite ends of the continuum cannot do so.
(The "ring" part of the term refers to the two ends of the interfertility continuum being located in the same geographic area, which is a red herring.)
As the wikipedia page notes, the problem that this concept exposes is that interfertility is not a transitive relation, and therefore can't be an equivalence relation.
> today on Facebook someone made the risible claim that since our DNA is 98% the same as a chimp, WE are "98% the same as a chimp."
> I pointed out that by that standard, we're also 60% the same as a banana.
The major problem here is that "to what degree is a person 'the same' as a chimp?" is not a well-defined question. Again, you would need to define what it means to be the same, and it will vary with what you care about.
There are important ways in which we are the same as a banana; most obviously, you can eat a banana and expect to be nourished. This is not a given for an alien organism, even one that appears to be largely chemically identical to a banana. Whether the similarities reach 60% depends on how you convert them to numbers. We can note that the concept of 'species' assures us that any two humans are 100% "the same", as compared to a banana, whereas if you research relatedness the convention is that two brothers are 50% "the same" and two strangers are 0% "the same" (and bananas, not being human, don't exist), and if you're doing theology the convention is generally that even identical twins are 0% "the same".
Summing that up, if you're told that two things are the same, the response is "the same how?" The reason the Facebook argument is stupid is that total shared DNA count isn't a useful thing to measure for most purposes. The salience of a difference in phenotype isn't closely related to the amount of DNA that changed to enable it.
What is with the "50k" in that headline?
The date of 50k years ago does not seem to appear anywhere in the linked academic paper, does not correspond to climate change at the start of the current interglacial, and does not correspond to evidence of the arrival of humans in North America. Even the body of the phys.org article doesn't say the extinction happened then.
It seems to me this data could be used to correlate a species/genus to a location if one knows where the samples came from. If one also knows the date of the geological strata the samples came from, then one also has a date correlation. A particular animal at a site at some time seems like information a researcher can use.
